The present invention relates to mechanical presses and in particular to flywheels subjected to press vibration, shock and long periods between clutch actuation.
Mechanical presses such as straight side presses and gap frame presses for stamping and drawing comprise a frame having a crown and bed and a slide supported within the frame for reciprocal motion toward and away from the bed. The slide is driven by a crankshaft having a connecting arm connected to the slide, to which is mounted the upper die. The lower die is mounted to a bolster which, in turn, is connected to the bed. Such mechanical presses are widely used for blanking and drawing operations and vary substantially in size and available tonnage depending on their intended use.
The primary source for stored mechanical energy and mechanical presses is the flywheel. The flywheel is located between the main drive motor and the clutch. The flywheel and flywheel bearing are mounted on either the driveshaft, crankshaft, or the press frame by use of a quill. The main drive motor replenishes the energy lost from the flywheel during press stamping operations when the clutch couples the flywheel to the press driven parts. During engagement of the clutch, the flywheel drops in speed and the press driven parts come up to press running speed. During engagement with the clutch, the flywheel rotates in unison with the clutch while the flywheel bearings have no relative rotation, except in the case of use of a quill where relative rotation is always present.
Prior art presses have a flywheel design where the flywheel is mounted to its support by means of anti-friction roller or ball bearings. Bearings of this type have characteristics of low lubrication requirements, low viscous drag, and a statistically predictable lifetime. These types of bearings have particular weaknesses to vibration and shock which may cause brinelling, false brinelling, fretting corrosion and damage to the bearing races, hub bores and shaft.